Created by ImPat on August 10, 2019
Step 1: Grease a 19cm x 30cm lamington pan and line base and sides with baking paper, extending paper 3cm above pan edges.
Step 2: To make topping, trim rhubarb stalks and cut into 5cm lengths.
Step 3: Peel apples and remove cores and cut apples into 2cm wedges and then spread rhubarb and apples, in a single layer, over an oven tray lined with baking paper and sprinkle with sugar and pour over water.
Step 4: Cook in a hot oven (200°c) for about 13 to 15 minutes, or until just tender and then remove and cool for 10 minutes.
Step 5: Beat butter, sugar and vanilla in a small bowl of an electric mixer and then beat in eggs, one at a time, until combined and then transfer to a large bowl.
Step 6: Sift combined flour, custard powder and baking powder over top and stir until combined and then spoon into prepared pan and smooth over top.
Step 7: Dollop custard over cake mixture and swirl through using a spoon being careful not to over-mix.
Step 8: Using tongs, arrange warm fruit over top.
Step 9: Cook in a moderately slow oven (160C) for about 1 hour, or until cake is cooked.
Step 10: Remove and stand in pan for 30 minutes.
Step 11: Serve warm cake with extra custard.